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Sept. 5, 2011 -- Even if they got one last year, most children should get another dose of the flu vaccine before flu season begins, according to the latest recommendations from the American Academy of Pediatrics (AAP).

The 2011-2012 flu vaccine protects against the same three strains of influenza as last year's. It's only the fourth time in 25 years that the composition of the flu vaccine has remained the same from one season to the next.

But researchers say a person's immunity to the flu drops by as much as 50% six to 12 months after vaccination, which is why annual vaccination is recommended for optimal protection.

The AAP recommends everyone over the age of 6 months receive the flu vaccine. Infants younger than 6 months are too young to receive the flu vaccine.

High-Risk Groups

Researchers say special efforts should be made to immunize those who are prone to influenza-related complications, including:

The AAP also recommends that parents, family members, household contacts, and caregivers of children younger than 5 years receive a flu shot to reduce the risk of complications.

At least 114 deaths of children were linked to influenza-related complications during the 2010-2011 flu season.

Vaccination Options

The flu shot is the only option for children between 6 months and 2 years of age. But most children over the age of 2 are also eligible to receive their dose of the flu vaccine via an intranasal mist or nasal spray.

Children between the ages of 6 months and 8 years should receive two doses of the flu vaccine for optimal protection if they did not receive any vaccine last flu season. The second dose is given four weeks after the first.

Researchers say most children with a history of mild egg allergy can safely receive the flu vaccine. But parents should consult an allergist before giving a flu vaccine to a child with severe egg allergies.